Seals for electrical connector assemblies are known. These seals include interfacial seals to sealingly engage mating connectors in connector assemblies, and environmental sealing arrangements to seal and securely retain insulated cables of individual terminated conductors within a connector body. For instance, U.S. Pat. No. 4,150,866 discloses a connector having a dielectric body with a plurality of contact-receiving cavities therein. A like plurality of insulated conductor wires with terminals thereon is inserted through individual elastomeric seals, and with the contacts secured in the forward ends of the cavities the seals sealingly grip the respective insulated coverings of the conductors and also sealingly engage side walls of the cavities at the rear of the connector body. With the particular shape of the seals, the seals are said to allow easy replacement of the contacts and to provide a wiping action between both the seal and connector and the seal and conductor to assure removal of any dirt or debris at the rear of the connector during removal of the contact, keeping the cavity clean.
Sealed connector assemblies find especial application where electrical connections are exposed to adverse environmental conditions either during performance or during servicing and repair of the connector or both. Adverse environmental conditions could include incidental water spray, high-nozzle-velocity water spray or steam such as during periodic cleaning, high humidity, and dust or debris. Typical uses for such a sealed connector would be in an electrical system for an agricultural tractor (where spray cleaning, dust and weather are involved) or air conditioner ducts (where high humidity is involved). It is foreseeable that such a connector assembly would need to be servicable in the field in that one of the contacts may need to be replaced in the connector. It is also foreseeable that an entire assembly may need to be applied to conductors in the field and therefore should require as few steps as possible in as simple and quick and effective a procedure as possible.
Such an assembly should have seals which do not provide inhibiting levels of resistance to the insertion of terminated conductors therethrough. Such an assembly should have seals which resist damage when a terminated conductor is being inserted therethrough, such as that which could arise because a terminal may have laterally projecting portions and corners which would tend to tear an elastomeric seal. This tendency would be greater for seals whose surface portions have substantial coefficients of friction.
Typically wire seals such as those discussed above are molded from elastomeric materials. The seals generally require surface lubrication before they are inserted into the connector housings. Additionally some lubrication means is also used before the wires having terminals terminated thereon are inserted into and through the seals. This is usually accomplished by dipping the wire members in a lubricating solution, such as alcohol immediately prior to insertion. The amount of lubrication needed depends upon the coefficient of friction of the insulating material on the conductor wire and the amount of seal surface that is in direct contact with the conductor wire as well as the amount of housing surface encountered by the outside of the wire seal as it is inserted into the connector and seated in its final position. The lubricant used on the outside surfaces is generally petroleum jelly or a mold release composition.
It is desirable to provide wire seals having inherent lubricity, which are capable of receiving terminated conductors having adjacent wire sizes.
The present invention is directed to a moldable mixture for molding sealing articles such as wire seals and annular rings that have inherent lubricity. Thus use of a wire seal molded from the moldable mixture of the present invention eliminates the aforementioned two lubrication steps in the manufacturing process. The inherent lubricity of the internal surface of the wire seal facilitates insertion therethrough of the terminal terminated on the end of the conductor wire. The inherent lubricity of the external surface allows the seals to be inserted into the housing and provides lubricity for any camming member required to deform the seal against the conductors extending therethrough. Furthermore, sealing members made in accordance with the invention can be preassembled into the connector. The end user of the connector need only insert the terminated conductor wires into the preassembled connector thus eliminating separate lubricating steps. The composition can be used to mold wire seals such as those disclosed in U.S. patent application Ser. No. 735,416 entitled Sealed Electrical Connector, filed concurrently herewith, U.S. Pat. No. 4,643,506 entitled Wire Seal filed concurrently herewith and Ser. No. 735,886 entitled Wire Seal filed concurrently herewith.
Annular sealing rings may also be molded from the moldable mixture. Electrical connectors are known which use annular sealing members to provide annular sealing between a plug portion of one dilectric connector housing and a hood or sleeve portion of a second dielectric connector housing therearound. Sealing is accomplished by the sealing member having compressive force applied around the circumference by the hood or sleeve portion being moved axially thereover while the sealing member is upheld by the plug portion underlying the sealing member, thus deforming the member which is of a relatively incompressible elastomeric material. Typically such sealing members are O-rings and tubular sleeves. One such annular sealing member is disclosed in U.S. Pat. No. 4,637,674 entitled Annular Connector Seal, filed concurrently herewith. Annular seals molded from the composition as disclosed herein have inherent lubricity and therefore a substantially lower coefficient of friction than compounds used heretofore.
It is known in the molding of articles to use mold release agents to facilitate removal of the molded article from the mold. DuPont Technical Bulletin NP-590.2, "Bloom in Compounds of Neoprene" by R. E. O'Sullivan, is directed toward the phenomenon of bloom in elastomeric compositions. The article states that bloom is primarily considered disadvantageous. One specific advantageous use being made, as the article points out, is the use of mold release agents during in-process molding of a moldable composition. It is not known, however, to produce articles having such blooming after molding and using such blooming advantageously during inservice use of the articles.